1. Field of the Invention
The present invention relates to a processing method of a thin-film in a thin-film wafer process and to a manufacturing method of a thin-film magnetic head using the processing method.
2. Description of the Related Art
In the thin-film wafer process for fabricating many thin-film magnetic heads on a wafer, formed are identification marks or addresses used for identifying each bar member with a plurality of aligned thin-film magnetic heads on the wafer or for identifying each thin-film magnetic head on the wafer.
U.S. Pat. Nos. 5,721,651 and 5,837,963 and U.S. Pat. No. 6,721,443 disclose methods each including steps of forming electromagnetic conversion elements and input/output electrodes on a wafer, depositing of a protection film thereon and forming identification marks on the deposited protection film by using a laser beam. If the identification marks are formed on the protection film that is the uppermost layer of the wafer as the methods disclosed in U.S. Pat. Nos. 5,721,651 and 5,837,963 and U.S. Pat. No. 6,721,443, it is possible to refer these identification marks after completing the wafer. However, such identification marks formed on the protection film can be utilized only in the processes executed after the protection film forming process. That is, in the upstream processes executed before the protection forming process, there is no such identification mark and therefore as a matter of course it is impossible to utilize such identification marks.
It is possible to form such identification marks or targets used as references for positioning the wafer in an upstream process executed before the protection film forming process. However, if an opaque film is formed on or above the formed identification marks or targets, it becomes impossible to refer these formed identification marks or targets in the downstream processes.
FIGS. 1a and 1b and FIGS. 2a and 2b are sectional views and plane views illustrating a part of a thin-film wafer process, used for providing an explanation about problems experienced by the inventors before the present invention. FIGS. 1a and 2a are A-A line sectional views of FIGS. 1b and 2b, respectively.
As shown in FIGS. 1a and 1b, when targets or addresses 12 and/or elements 13 are formed on a certain film 10 laminated on a wafer and a transparent film 14 such as an Al2O3 film is formed thereon, the targets or addresses 12 and the elements 13 can be seen through the transparent film 14 and thus can be referred at this stage.
However, as shown in FIGS. 2a and 2b, if an opaque film 16 such as a seed layer for plating for example is deposited thereon, the targets or addresses 12 and the elements 13 cannot be seen because they are hidden behind the opaque film 16. Therefore, in this case, it is impossible to use the targets or addresses 12 as references for positioning the wafer in the downstream processes and also it is impossible to identify the elements 13.